Role of Ocular Ultrasonography to Distinguish Papilledema From Pseudopapilledema.

BACKGROUND: We prospectively evaluated the sensitivity and specificity of ocular ultrasonography (OUS) to distinguish papilledema from pseudopapilledema. METHODS: Forty-nine study participants, with optic disc elevation, underwent neuro-ophthalmic evaluation, OUS, fundus photography, and optical coherence tomography (OCT) of the optic nerve head at the initial and follow-up visits (≤6 months apart). Participants were classified as having papilledema if there was a change in optic nerve appearance on fundus photographs, as determined by a masked observer, between initial and follow-up visits ≤6 months apart. OUS was considered positive when the optic nerve sheath width was >3.3 mm and the 30° test was positive. Ocular ultrasonographic findings were correlated in patients who had papilledema vs patients who had pseudopapilledema. In a subanalysis, OUS findings were also correlated with change in peripapillary retinal nerve fiber layer thickness on OCT of the optic nerve head between initial and follow-up visits. RESULTS: OUS was 68% (17/25) sensitive for papilledema and 54% (13/24) specific for pseudopapilledema. When using OCT parameters to define papilledema, the sensitivity of OUS to diagnose papilledema decreased to 62%. Positive OUS correlated with elevated opening pressure on lumbar puncture and with signs of increased intracranial pressure on MRI. CONCLUSION: OUS alone was less sensitive in diagnosing papilledema than previously thought. Therefore, OUS may not be helpful in distinguishing between papilledema and pseudopapilledema.

The obstructive sleep apnoea syndrome in adolescents.

BACKGROUND: The obstructive sleep apnoea syndrome (OSAS) results from a combination of structural and neuromotor factors; however, the relative contributions of these factors have not been studied during the important developmental phase of adolescence. We hypothesised that adenotonsillar volume (ATV), nasopharyngeal airway volume (NPAV), upper airway critical closing pressure (Pcrit) in the hypotonic and activated neuromotor states, upper airway electromyographic response to subatmospheric pressure and the ventilatory response to CO2 during sleep would be major predictors of OSAS risk. METHODS: 42 obese adolescents with OSAS and 37 weight-matched controls underwent upper airway MRI, measurements of Pcrit, genioglossal electromyography and ventilatory response to CO2 during wakefulness and sleep. RESULTS: ATV, NPAV, activated and hypotonic Pcrit, genioglossal electromyography and ventilatory response to CO2 during sleep were all associated with OSAS risk. Multivariate models adjusted for age, gender, body mass index and race indicated that ATV, NPAV and activated Pcrit each independently affected apnoea risk in adolescents; genioglossal electromyography was independently associated in a reduced sample. There was significant interaction between NPAV and activated Pcrit (p=0.021), with activated Pcrit more strongly associated with OSAS in adolescents with larger NPAVs and NPAV more strongly associated with OSAS in adolescents with more negative activated closing pressure. CONCLUSIONS: OSAS in adolescents is mediated by a combination of anatomic (ATV, NPAV) and neuromotor factors (activated Pcrit). This may have important implications for the management of OSAS in adolescents.

Understanding the anatomic basis for obstructive sleep apnea syndrome in adolescents.

RATIONALE: Structural risk factors for obstructive sleep apnea syndrome (OSAS) in adolescents have not been well characterized. Because many adolescents with OSAS are obese, we hypothesized that the anatomic OSAS risk factors would be more similar to those in adults than those in children. OBJECTIVES: To investigate the anatomic risk factors in adolescents with OSAS compared with obese and lean control subjects using magnetic resonance imaging (MRI). METHODS: Three groups of adolescents (age range: 12-16 yr) underwent MRI: obese individuals with OSAS (n = 49), obese control subjects (n = 38), and lean control subjects (n = 50). MEASUREMENTS AND MAIN RESULTS: We studied 137 subjects and found that (1) obese adolescents with OSAS had increased adenotonsillar tissue compared with obese and lean control subjects; (2) obese OSAS adolescents had a smaller nasopharyngeal airway than control subjects; (3) the size of other upper airway soft tissue structures (volume of the tongue, parapharyngeal fat pads, lateral walls, and soft palate) was similar between subjects with OSAS and obese control subjects; (4) although there were no major craniofacial abnormalities in most of the adolescents with OSAS, the ratio of soft tissue to craniofacial space surrounding the airway was increased; and (5) there were sex differences in the pattern of lymphoid proliferation. CONCLUSIONS: Increased size of the pharyngeal lymphoid tissue, rather than enlargement of the upper airway soft tissue structures, is the primary anatomic risk factor for OSAS in obese adolescents. These results are important for clinical decision making and suggest that adenotonsillectomy should be considered as the initial treatment for OSAS in obese adolescents, a group that has poor continuous positive airway pressure adherence and difficulty in achieving weight loss.